Question

Find the tenth term of the geometric sequence, given the first term and common ratio.

Answer 1

Answer:

$a_{10}=\dfrac{1}{128}$

Step-by-step explanation:

In the geometric series:

$a_1=4\\ \\r=\dfrac{1}{2}$

The nth term of the geometric sequence can be calculated using formula

$a_n=a_1\cdot r^{n-1}$

In your case, n = 10, then

$a_{10}\\ \\=4\cdot \left(\dfrac{1}{2}\right)^{10-1}\\ \\=4\cdot \left(\dfrac{1}{2}\right)^9\\ \\=2^2\cdot \dfrac{1}{2^9}\\ \\=\dfrac{1}{2^{9-2}}\\ \\=\dfrac{1}{2^7}\\ \\=\dfrac{1}{128}$